Telephone-exchange system



' Dec. 29, 1925 1,567,261 E. s.- GIBSON TELEPHONE EXCHANGE SYSTEM Filed Sept. 28, 1923 3 Sheets-Sheet -1 Myer/fan- [Jr/J 072.100

Dec. 29, I925- 1,567,261 E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Filed Sept. 28, 1923 3 Sheets-Sheet 2 r/o. mm; W my Dec. 29, 1925- 1,567,261

E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Filed Sept. 28, 1923 3 Sheets-Sheet 3 Patented Dec. 29, 1925.

osin stare End EARL S. GIBSON, F RIDGEWOGD, NEW JERSEY, ASSIGNOQ COMPANY, INCORI'ORATED, OF NEW YORK, N. 1 A 0 r0 wnsrnnn ELECTRIC nrona'rron or new YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed September 28, 1923.

tain new and useful Improvements in Telephone-Exchange Systems, of which the following 1s a full, clear, concise, and exact description.

' This invention, relates to telephone exchange systems, and especially to systems employing automatic switching apparatus for the establishment of connectlons.

.The object ofthis invention is to more uniformly distribute the load of switch controlling mechanisms by taking them into use in different orders through the medium of.

, selecting devices.

21 feature ofthe invention is the provision of a system in which central office control- .ling senders are divided in groups, each group appearing as first choice in a different selector switch and all switches having access to all groups of senders.

A further feature relates to the arrangement ofthe sender selector switch control circuits whereby when one of the switches finds all of its first choice senders busy, its control circuit coacts with the control circuit of another selector to enable the selection of one of its second choice senders.

These and other features of the invention will be more fully explained in the following detailed description and also in the appended claims.

Referring to the drawing, Figs. 1 and 2,

when taken in order, with Fig. 3 below Fig. 2, disclose a sufficient amount of a telephone system to enable an understanding of the invention.

Fig. 1 shows diag 'annnatically a subscribers line and aline switch together with an outgoing trunk circuit and certain controlling equipment.

Fig. 2 shows one of a plurality of coordinate sender selector switches for associating the central ofiice register senders with calling lines.

Fig. 3 shows a second sender selector switch serving in the same capacity.

In the system disclosed, register senders of the cent al olfice type are employed for recording designations sent over subscribers lines for the purpose of controlling switches in the office to establish the desired connec- Serial No. 565,309.

tions. At the bottom or" Fig. 3 there are shown diag 'ammatically'. four of these central office senders 311, 312, 313 and 311 In order that the senders may be associated with the calling lines which are extended through line switches 101 to trunks 102, there are provided a number of sender selector switches. Two of these switches, 200 and 800, are shown in detail in the drawing.

Several trunks, such as the trunk 102, ex: tending from the line switches to a repeating coil 103 and thence to a first automatic selector switch (the latter not being shown) are arranged to appear in the sender selcctor switches. The particular trunk 102 shown in the drawing appears in the vertical row of contacts 205 in the sender selector switch 200, having access to all of the horizontal links in the group containing the links 201 and 202. Other trunks may have an appearance in the same vertical row 205, the one being illustrated having an appearance before the group of links containing the links 203 and 20%. Likewise, other trunks appear in other vertical rows such as the row 206. Similarly, trunks from the same or other line switches appear in the second sender selector switch 300 in the vertical rows 301, 302, etc.

For reasons to be more fully explained hereinafter, the sender selector switches are arranged in pairs. The entire number of senders available to the sender selector switches 200 and 300 are divided into two groups. The first group contains the send ers 311 and 5:112, which appear by means of the connecting circuits 211 and 212, respectively, as first choice senders in the selector switch 200. The connecting circuits 211 and 212 occupy the vertical rows of cone. tacts 210 and 209, being accessible to all of the horizontal links in the switch 200. These same senders appear in the second selector switch 300 in the vertical rows 30-1 and 303 as second choice senders. In like manner, the second group of senders, of which two, 313 and 31-1, are shown, appear in vertical rows 208 and 207 of the selector switch 200 as second choice senders. Furthermore, this second group of senders by means of connecting circuits such as the circuits 213 and 2L1 also are multipled to appear in the vertical rows 00%; and 305 of the second selector switch 300 as first choice :aL.;i'Lil3l'5. It will be understood, of course,

that the capacity of the sender selector switches may be taken at any convenient value to accommodate as many senders in each group as may be desired.

The sender selector switches 200 and 300 are of the coordinate type, being equipped with a number of horizontal link circuits and a number of rows of contacts representing incoming and outgoing circuits. Each of the vertical rows and each of the horizontal links is provided with an operating bar, which cooperate with each other to establish connections through the switches. Regarding the selector switch 200, the magnets 215, 216, 217, 218, 219, etc., operate the vertical bars relative to the rows 205, 207 and 203, etc. The horizontal magnets 235 and 236 operate the horizontal bars individual to the links 201 and 202. F or a more detailed explanation of the structure and operation of switches of this character, reference is made to the patent to C. L. Goodrum and J. N. Reynolds, No. 1,515,735, issued Nov. 18, 192 1, and the patout to S. B. Williams, No. 1517,331, granted Dec. 2, 1924 The selector switch 200 is provided with a master cont-rolling arrangement consisting of relays, shown at the bottom of Fig. 2. The switch 300 is likewise provided with 'a master controlling equipment. The operation is such that if one of the selector switches finds all of its first choice senders busy, the master controlling mechanism of the other selector switch is brought into action in such a manner that the first selector swi ch will be caused to choose one of the second choice senders. In other words, either switch failing to find one of its first choice senders idle, will be influenced by the master cont-rolling mechanism of the other switch to establish connections to one of its second choice senders.

Taking up the operation of the system in detail, assume that the subscriber on line 100 initiates a call. In any well known manner the line switch 101 operates and the calling line is extended over the trunk 102, which contains the repeating coil 103, and leads to a first group selector switch (not shown). Vvhile the line switch 101 is operating, ground potential may be placed on the sleeve conductor llt, whereupon relays 107 and 224 operate over a circuit through the normal contacts of slow to release relay 106, winding of relay 107, conductor 115, winding of relay 22 1, to battery. Relay 107 is individual to the trunk 102 in the sender selector switch 200. Relay 107 in operating closes a locking circuit for itself through its winding and outer left contact to ground at the lowermost contact of relay 104C. Relay 107 also closes a circuit from battery through the winding of slow relay 106 to ground at the inner left contact of relay 107. Relay 224 in operating closes a circuit from ground through its contact, right contact of relay 225, winding of relay 226 to battery. Relay 226 operates and a circuit is closed from battery through the right hand winding of the vertical group relay 227, right front con tact of relay 226, right back contact of relay 237, left contact of relay 232, conductor 238 to ground at the normal contact of relay 233. Relay 227, which is individual to the vertical group 205, operates and closes a circuit from battery, through its left hand winding and front contact, left back contact of vertical group relay 239, winding of relay 232 to ground on conductor 238. Relay 232 operates and a circuit is closed from the grounded conductor 238, left front contact of relay 232, lowermost contact and the outer right armature of relay 227, winding of the vertical operating magnet 215 to battery. Magnet 215 operates and prepares the contacts in a vertical row 205. Magnet 215 at its innermost cont-act closes an obvious circuit for relay 225. Relay 225 opens the circuit of relay 226, which releases. Another circuit may be traced from the grounded conductor 238, front contact of relay 232, upper contact and the right hand outer armature of relay 227, conductor 240, normal. contact of relay 23 1, conductor 241, uppermost contact of the trunk relay 223, windin of the vertical operating magnet 219 to battery. It is assumed that the first sender 311 of the group which is first choice to the sender selector switch 200 is idle at this time. Therefore, the relay 223, which is individual to the circuit 211, is deenergized and the circuit above traced is completed for the corresponding vertical magnet 219. Magnet 219 in operating prepares the contacts in the vertical row 210.

With relay 227, operated, a further circuit is completed from ground over conductor 238, contact of relay 231, conductor 241-1, inner right contact of relay 227, conductor 2 15, right contact of relay 107, back contact of relay 108, upper winding of the horizontal group relay 109 to battery. Relay 109, which is common to the links of the horizontal group containing the links 201, 202, etc., operates and closes a circuitthrough its lower winding and front contact, lower inner back contact of horizontal group relay 117, conductor 118, winding of relay 231, to ground on conductor 238, causing relay 231 to operate. Relav 109 at its lowermost front contact closes a circuit for relay 110.

lVith relay 110 operated, a start circuit completed for operating the horizontal mag net associated with the first idle link in the group. This circuit may be traced from ground through the left contact of magnet 219, conductor 2 12, outer left contact of magnet 215, conductor 243, lowermost contact of relay 110, inner left front contact of relay 112, assuming the link 202 to be busy, inner left back contact of relay 111, assuming the link201 to be idle, right hand winding of the horizontal operating magnet 235 to battery. Magnet 235 operates and effects connection between the conductors of the inconiing circuit 102 and the horizontal link 2011, and also between the horizontal link 201 and the circuit 211 leading to the idle sender 311. Upon the operation of the switch200, the following circuit is closed for holding the magnet 235 temporarily: battery, through the windings of said mag net, winding of relay 111, test conductor of the horizontal link 201, contacts of the switch 200, thence over conductor 246 to ground at the right front contact of the vertical magnet 219. The relay 111 does not operate in this circuit since it is shunted the circuit of relays 109 and 231.

by the original operating circuit of magnet Another circuit is closed from ground over the conductor 246 through contacts of the switch 200, thence over conductor 247,

.winding of relay 104 to battery. Relay 104 operates and opens the circuit of relay 107.

Relay 107 opens the circuit of relay 106, but before relay 106 can become deenergized, a substitute cireuit is closed therefor as follows: battery, through the winding of said relay, middle lower contact of relay 104, contact of relay 106 to ground,

Immediately that the switch 200 operates, the tip and ring conductors of the trunk circuit 102 are extended through to the sender 311, resulting in the closure of the following circuit: battery, through the winding of relay 315, outer contact of relay 316, conductor 318, contacts of the switch 200, conductor 248, thence through line switch 101 over the calling subscribers line 100 and returning over the other side of the line through the switch 101, conductor 249. throughthe switch 200, conductor 319,inner contact of relay 316, winding of coil 317 to ground. Relay 315 operates and closes a circuit for slow relay 320. Relay 320 operates and applies ground potential to the holding conductor 246. y

, At the time the horizontal operating magnet 235 actuates, a circuit is closed from ground through the lowermost contact of relay 109,;left contact of magnet 235, right contact of relay 111, thence over conductor 119, winding of the release relay 233 to battery. Relay 233 operates and removes ground potential from the conductor 238,

whereupon the ertical magnets 215 and 219 become deenergized.

Magnet 215 releases the relay 225. Relay-233-also opens the circuit of relays 232 and 227 and also Relay 109 turn releases the relay 110. WVith magnets 215 and 219 released, the connection through the switch is maintained by the continued energization of the horizontal magnet 235. Relay 110 in releasing removes the shunt from around the winding of relay 111, and this relay operates in series with magnet 235. \Vhen magnet 219 releases, a circuit is closed from battery through the upper winding of relay 223, right back contact of magnet 219, conductor 246 to ground at the armature of relay 320. The relay 223 operates, and looks through its lower winding; its upper armature extends the start wire 241 through to the next relay 222 representing the second sender in the preferred group.

After the sender has completed its functions in the well known manner, it may be released by operating the relay 316. hen relay 320 releases, it removes ground from conductor 246, whereupon the horizontal magnet 235 and relay 111 become deenergized and the connection through the selector switch 200 is restored to normal. The disconnection of the sender from the trunk circuit 102 brings about the release of relay 104. l/Vhen relay 104 releases, the calling subscribers line 100 is extended through to the left hand windings of the repeating coil 103 and relay 105 operates to maintain the slow relay 106 operated.

When the connection is no longer required the subscriber restores the receiver to the switchhook whereupon release takes place in the Well knowh manner.

It will next be assumed that all of. the senders of the group which are first choice to the switch 200 are busy at the time it is desired to associate a sender with the trunk circuit 102. Since all of these senders are busy, the relays 223, 222, etc., related to the first group, are energized. hen, theretacts of relays 223 and 222. thence over conductor 250, winding of relay 234 to battery. Relay 234 operates and locks through its outer right contact, conductor 240, contact of relay 227, left contact of relay 232 to the grounded conductor 238. Relay 234 completes a circuit from the grounded conductor 238 through its outer left contact, conductor 251, right contact of relay 352, winding of relay 353 to battery. Relay 353 operates and a circuit is closed from battery through the right hand winding of relay 354 right contact of relay 353, right back contact of relay 355, right back contact of relay 356, back contact of relay 357 to ground at the contact of relay 358. Relay 354 operates and closes a circuit from battery through its left winding and contact, left back contact of relays 359 and 360, winding of relay 357 to ground at the contact of relay 358. Relay 357 operates and a circuitis completed from ground through the contact of relay 358. front contact of relay 357, outer right contact of relay 354,

conductor 261, inner right contactof relay 234,- thence over the start wire 262, through the upper back contact of relay 221, winding of the'vertical magnet 217 to battery! ,{The magnet 217 is operated, preparing the contacts representing the first idle sender in the groupwhich is second choice to the sender selector switch 200. This is the 's'ender313. With magnet 217 operated, 'a circuitis closed from ground through its left contact, over conductor 242 and thence *inthe manner above traced. From this point on the selectionof the first idle hori- "zontal link in the proper group and the operation of the-horizontal magnet takes place in the manner above described.

' lNhen the release relay 233 is operated, as above explained, a circuit is closed from ground through its right contact, conductor 260, inner right contact of relay 354, winding of release relay 358 to battery. Relay 358 in operating causes the release of relays 357' and 354. 'i

' It will be noted that'the masterorcontrolling circuits of either of the switches when taken for use in connection with the other switch guards against interference by preventing both switches from making connection to the trunk at the same time.

' While the description has been given with respect to the switch 200, it will be obvious from inspection of the circuits] that the switch 300 operates in the same manner and 'may-serve to extend connections to senders, either of the first choice or of the second choicefgroup.

What is claimed is:

1, In combination, a plurality of central ,ofiice senders, a connecting circuit for each of said senders, a plurality of selective switches in which said'circuits appear, each switch having access to a different portion of said senders as first choice and to the remainder of said senders as second choice, and means for operating one of said switches to select the connecting circuit individual to any one of said senders.

2. In combination, a plurality of central office controlling senders, a plurality of selective switches. said senders being arranged in groups, each group of senders appearing in each of said switches, and means for operating each of said switches to select the senders in a different one of said groups as first choice and to selec senders in another group assecond choice.

' -3. In combination, a plurality of central oflice senders, a plurality of selector switches, connecting circuits, one leading to each of said senders, said circuits being arranged "in groups and each group appearing in all of said switches. said switches arranged to select one of said groups of circuits as first choice and another] of said groups as second choice, and means for operating'said switches to choose the first idle circuit in either group. I

4.111 combination, a plurality'of switches, lines incoming'to said switches, a plurality of senders, lines interconnecting said switches and senders, each of said switches having access to the lines leading to a different portion of said senders as first-choice and to the lines leading to the remaining senders as second choice, and means for operating any switch to extend an incoming line to, an idle sender whether of the first choice or of the second choice.

5. In combination, incoming lines, a plurality of central office senders, circuits for each of said senders switches having intermediate links for connecting the incoming lines to the circuits leading to said senders,

each of said switches having access as first choice to a different portion of said senders, and means for operating any switch to select either a sender in the first choice group or a sender in the second choice group.

6. In combination, a plurality of central oflice senders, a connecting circuit for each sender, a plurality of coordinateswitches in which said circuits appear, each switch having access to a different portion of said senders as first choice and to other of said senders as second choice, and means for operatingone of said switches to select the circuit individual to any one of said senders.

7. In combination, a plurality of senders, a connecting circuit leading to each of said senders, two selector switches in which said circuits appear, each switch having accessto a different portion of said circuits'as first choice and to the remainder ofsaid circuits as second choice, a master circuit for controlling the operation of each of said switches, and means when all of the circuits which are first choice to one of the switches are busy for rendering the master circuit associated with the other switch effective to cause said first mentioned switch toselect one of its second choice circuits. y

8. In combination, a plurality of senders, two selector switches, each switch having access to a different portionof said senders as first choice and to the remainder as second choice. a master circuit forcontrolling the operation of each of saidswitches', means when all of the circuits which are first choice to one of the switches are busy for rendering the master circuit associated with the other switch effective to causethe first mentioned switch to select one of its second choice senders, and means for preventing the second switch from selecting oneof its second choice senders.

In witness whereof, I hereunto subscribe my name this 25th day of September, A. D. 1923. I

EARL s. GIBSON. 

